How to grow mushrooms on logs – part 1

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Grow a mushroom garden

Growing ‘shrooms on the homestead often requires sterile technique, that is beyond the scope of most homestead environments. Tissue culture in grain is a hit or miss activity. Mold often spoils a jar of rye seed before the mushroom mycelium has a chance to colonize a jar. For this reason it’s best to do only small jars of tissue culture so that any spoilage is minimized. To increase success commercial mushroom growers have sterile glove boxes, HEPA filters, and expensive flow hoods in a laboratory environment, to minimize contamination of mushroom cultures while doing culture transfers. The expense and the need for special training in sterile culture transfer is enough to discourage most would-be mushroom farmers before they even get started.

But there are several ways to cultivate mushrooms that don’t require a sterile laboratory set up. Log cultivation of mushrooms is one of the easiest ways to grow mushrooms on the homestead. In log cultivation newly felled trees are inoculated with mushroom fungus and allowed to mature over a season. Once the mycelium has run through the log, and the humidity and temperature are right for the specific mushroom species, the log will fruit, producing a flush or even two of mushrooms, ready to harvest. The log may fruit twice once in spring and again in fall. The log will continue to produce mushrooms for 4 to 6 years before being fully consumed by the fungus. Mushrooms can be a short lived perennial for your homestead when you grow mushrooms on logs.

What yields can I expect?

On average a 4 foot log that is 4 inches in diameter will produce 1 lb of mushrooms each year for 4 years, depending on the type of log. A mushroom garden with 30 logs will give you, on average, 30# of mushrooms divided by two harvest periods. Excess mushrooms can be dried, cooked in sauces and canned or frozen. Mushrooms that are dried in the sun increase their vitamin D content, an important vitamin for the winter months.

Shiitake Mushrooms

What species of mushrooms should I choose?

Shiitake mushrooms and Oyster mushrooms are the easiest mushrooms for a beginner to grow. Other mushrooms suited to log cultivation include Reishi mushrooms, Lions Mane Mushrooms, Maitake, and Chicken of the Woods. Save these for cultivating once you’ve had some success with Shiitake and Oyster mushrooms. They are a little trickier and are fussier in the type of wood they fruit on.

There are several strains of both Shiitake and Oyster mushroom to choose from. Check the ideal fruiting temperatures for each variety when making your selections. If you live in Canada your selection will be more limited. At this writing (2015) mushroom cultures imported into Canada from the USA require a USDA phytosanitary certificate, but not an import permit. I found two sources for mushroom starts in Canada. Mycosource has sawdust spawn for 1 variety of Shiitake mushroom and for “Grey Dove” Oyster mushrooms. MycoBoutique in Quebec has these varieties, as well as the more exotic mushrooms in dowel plugs available for log cultivation. Check the requirements of your own country before importing myceliated plugs or sawdust. There are restrictions for importing mushroom cultures to the state of Hawaii, as well.

Ordering sawdust spawn or mushroom plugs

You’ll need to order your spawned sawdust or mushroom plugs at least 4 weeks before you want to cultivate your logs. If you order sawdust, you may find heavily myceliated areas in the bag, where the sawdust is completely crusted in white or beige mycelium. There might even be buttons and mushrooms beginning to form. Just break these apart in the bag with the bag still sealed. The tool you use to push sawdust into the logs will help to break these apart, too. If you remove them from the bag, you’ll find that you don’t have much sawdust left to use. The mushrooms don’t begin to fruit until they’ve consumed their substrate, so by the time you see buttons forming a lot of the sawdust has been consumed by the fungi.

How to prepare your logs

Hardwood logs are used for mushroom cultivation. You won’t find very many edible mushrooms growing on conifers. The piney resins inhibit fungal colonization. I used alder for Shiitake mushrooms and Aspen for Oyster mushrooms in my mushroom project. Oak, maple, cottonwood, poplar and several other hardwoods can be used successfully. If you live in the east where hardwood forests are the norm, lucky you! You’ll find lots of suitable trees in woods near you. Oak and maple are prime. These hardwood logs will give you a few more years of mushroom harvests on each log, compared to the trees I have available here in BC.

Logs that have been lying on the ground for more than 6 months are not suitable for mushroom cultivation.

Prepare your logs by felling fresh trees in the dormant season. Ideally you’ll want to cut down the trees before they leaf out in the spring. This is when the nutrition and sugars are highest in the tree. Look for trees that are 4 to 6 inches in diameter that are free of fungal disease.

You can plug larger logs but they are heavier and more difficult to move and to handle. Cut the logs into 4 foot lengths or to the length that you can easily handle. You’ll need to move the logs occasionally to put them into the ideal position for working with them and then move them again into their fruiting position. So take this into account when you are deciding on how long to cut your logs. Smaller logs tend to dry out faster, though.

Freshly cut logs should be allowed to lie, supported, off the ground, for a month before inoculating. This allows the antifungal activity in the log to stop. The stumps can also be inoculated with sawdust spawn or spawned dowel plugs.

After you’ve plugged the logs you’ll want to keep them in the shade to prevent them from drying out. If you are in an area that doesn’t get much rain, you’ll also want to water them at least once a week to keep the moisture level high and encourage the spawn run.

The ideal mushroom yard is…

In a shady area under the tree canopy. If you lack shade you can set up a shade cloth over a hoop house to keep your logs protected from the drying rays of the sun.

A fenced area so that you can keep livestock from damaging your cultivated logs and keep creatures away from your fruiting mushrooms. Goats love to jump on logs. That won’t be good. A fence is good.

A spot that you can easily get supplemental water to the logs during the summer

With space to move logs around for the resting period, where you want the logs close to the ground, but not on the ground, to keep humidity levels high, and where you can place the logs upright for fruiting.

A place with room for a soaking tub, where you can soak the logs to encourage fruiting during the growing season. You can promote fruiting by soaking the logs for 24 hours during the growing season.

A place with room to expand so that you can add fresh logs annually. You can create a perpetual mushroom garden by adding 10 logs of oyster and shiitake mushrooms each year. After 4 years you’ll be getting 80 to 100 lbs of mushrooms a year – 1 lb of mushrooms per log. When shiitake mushrooms are selling for $15 a lb, that’s a tidy profit from your mushroom project, just selling what your own family doesn’t eat.

A spot where you can protect the logs from pests and predators with landscape fabric and agricultural cloth.

What if a tree falls in the middle of the summer and I want to inoculate the log for mushrooms?

Do it. You only have one chance to decide what kind of fungus will grow in the tree. Guaranteed at least one will colonize it, so you might as well pick which one. While summer inoculation isn’t the ideal, it can’t hurt to try. Wait at least a month after taking the tree down to allow the antifungal activity in the living tree to stop. Inoculate with spawn plugs or sawdust spawn and then keep the tree damp, by watering it in dry spells. You should see evidence of spawn run in 4 to 6 months.

Proceed with caution. A tree laying on the ground can be colonized by less desirable fungi. Know how your species of mushrooms looks before you decide to eat it. Oyster mushrooms and Shiitake mushrooms have a distinctive pleasant mushroom smell, similar to the smell of button mushrooms. When you see the right kind of mushroom starting to fruit on your logs, stand your logs up against a support to make harvest easier, if possible. If the log is too big to move, which might be the case if you innoculate a fallen tree, just harvest the mushrooms where they grow.

See part 2 – How to Grow Mushrooms – Inoculating the logs and preparing your laying yard.

Your Turn:

I’d love to hear about your experience growing a mushroom garden. I’m eager to learn all I can about these beneficial fungi. Tell me your story in the comments.

Hello, I’m on the Big Island of Hawaii, and just got my mixed variety order of plug and sawdust spawn. I live in native Ohia forest, with some invasive guava trees, and cut some logs of eucalyptus from a fallen tree along the highway. Any idea what species will do well on Ohia, and guava logs? Ohia is a very hard wood, but may contain natural antimicrobial chemicals, as even old logs are slow to decompose. I hear shiitake will work on the eucalyptus, but I’m not sure if the reishi and oysters will like the local woods I have available, as there aren’t any of the typical hardwoods available. Also we receive 175+ inches of rain annually so excessive moisture may be a concern. I’ll likely store logs vertical to avoid over watering. I guess I’ll just have to try various wood, and conditions, but if you have any ideas, or references to using these woods in Hawaii would be appreciated. Many thanks for your article!

It depends on how long it takes for the mycelium to permeate the logs. Larger logs take longer. Also the average temperatures where you live contribute to how long it takes. Warmer temperatures make the mycelium run faster throughout the log.

I live in NW Wisconsin, I have access to Oak logs but we have lots of what we call Popple or what is really Aspen. i saw the pictures of the logs you have and it looks just like our Popple (aspen) so I am intrigued and interested if it is OK to use this wood to grow mushrooms up here. I can get all kinds of Popple logs very easily and would like to grow mushrooms with these type of logs if possible. Tell me I can do this this way and I will cut down some popples and order mushroom cultures . i am somewhat excited about this idea. Thanks for your help.

Yes we used aspen and alder for our mushroom logs. Oak logs will give you a longer log life for mushroom harvests because the wood is denser. But we don’t have oak or maple here. Aspen works for oyster mushrooms. Oak is good for shiitake, and we would have used that if we had any growing. Your best bet is to talk to the farm where you’ll purchase your spawn from. There are different mushroom varieties suited to different woods and your best to get a specific variety that is suited to the wood you have. Oyster mushrooms are quite adaptable. Shiitake are a little more persnickety.

I’ve been trying to grow shiitakes on oak logs over the last year here in Shropshire UK. I’ve followed the instructions but so far no luck, I think I’ve been letting the logs dry out too much. Thanks for your article, I’ll keep trying!